Photographic process printers use a cathode ray tube (CRT) to project an image onto a photosensitive media. After the image is projected onto the media, the media is processed to develop the latent image. In order to transfer the image from the surface of the CRT to the surface of the media while maintaining image focus, an array of optical fibers are adapted to transfer the light from the surface of the CRT to the surface of the media.
A problem exists when applying this technology to create wide format images on wide format photosensitive media. Large CRTs are inherently complex in their design due to factors relating to the wide ranging sweep of the electron beam within the CRT and the difficulty of manufacturing a large glass envelope. Retaining the quality required for the print process of photographic printer devices requires large CRTs representing significant cost and complexity in the resulting photographic printer device. A practical limit on the CRT width in these applications is less than the width desired for wide format photosensitive media.
One apparent option is to divide the image horizontally onto a plurality of smaller CRTs. This option presents problems in that CRTs cannot be physically mounted horizontally adjacent one another so as to create a seamless horizontal image row. All known CRT devices are manufactured with some non-imageable area at their horizontal sweep limits. Additionally, physical thickness of the CRT glass envelope material will preclude precise, horizontal, seamless alignment of the plurality of partial images on the CRTs.
Although optical fibers are used to transfer the image from the projection surface of each CRT onto the surface of the photosensitive media, these fibers must remain short enough to prevent excessive loss of image light intensity. The short length of the optical fibers precludes physical recomposition of the whole image by simply bending the optical fibers so that the fibers at the ends of adjacent partial image segments are abutted.
It is thus apparent that there is a need in the art for an improved method or apparatus which permits efficient transfer of a wide format image onto photosensitive media from a plurality of CRTs.